Fig. 1
Using SAM as a methyl group donor, NSUN2 catalyzes cytosine-5 methylation in the CDS and 3′-UTR of mRNA. The enrichment of m5C deposition in the CDS inhibits mRNA translation efficiency. In contrast, by cooperating with m6A methylation, which is modulated by MTTL3/MTTL14, m5C methylation in the 3′-UTR of mRNA promotes mRNA translation and protein synthesis. SAM: S-adenosyl-methionine, SAH: S-adenosyl-homocysteine